Venturi tube with air shutter



Dec. 3, 1957 C, C, LAMAR VENTURI TUBE WITH AIR SHUTTER Filed, April '7, 1955 ATTORNEYS United States Patent O VENTURI TUBE WITH AIR SHUTTER Charles C. Lamar, Chicago, lll., assignor to Harper- Wyman Company, Chicago, Ill., a corporation of Illinois Application April 7, 1955, Serial No. 499,847

Claims. (Cl. 158-118) The present invention relates to venturi tubes and more particularly to venturi tubes which are used to supply a combustible mixture of gas and air to gas burners. It has for its primary object the provision of a new and improved stamped venturi and assembly of the venturi with an air shutter.

A further object of the present invention is the provision of a new and improved thin walled metallic venturi tube having uniform diameter tubular inlet and outlet ends and an intermediate nned venturi section which includes a throat and associated oppositely extending and diverging portion, and in which the fins have an outside dimension corresponding to the outside diameter of the tubular inlet and outlet ends whereby an air shutter may be slidably mounted upon and supported in part by the tins and in part by the inlet end of the tube.

A further object ot' the present invention is the provision of a new and improved stamped venturi tube which comprises a tube having a venturi section including a restricted throat and converging inlet and diverging outlet portions with which are associated a plurality of ns Whose outer sides are parallel and the dimensions of which correspond to the outside diameter of the tube.

In brief, the venturi tube of the present invention cornprises a tube of uniform diameter with inlet and outlet ends and an intermediate venturi section having a throat and converging inlet and diverging outlet portions. The throat and inlet and outlet portions are provided with a plurality, such as four, tins formed by doubling portions of the tube wall so that the outer dimensions of the fins remain the same as the outside diameter of the tube and so that their outer sides are parallel. The outlet end of the tube may be configured as by bending or the like for the reception of burner supporting means. The inlet end of the tube is apertured to provide air inlets, the effective size of which is controlled by a slidable air shutter supported by the fins and the inlet end of the tube.

Other objects and advantages of the present invention will become apparent from the ensuing description of an embodiment thereof, in the course of which reference will be had to the accompanying drawing, in which:

Fig. 1 is a side elevational view, partly broken away, of a venturi tube constructed in accordance with the present invention and showing the tube in relation to the outlet nozzle of a gas valve;

Fig. 2 is an end View taken along the line 2-2 of Fig. l, with the nozzle omitted;

Figs. 3 and 4 are transverse cross-sectional views taken along the lines 3-3 and 4-4, respectively, of Fig. l;

Fig. 5 is a fragmentary axial cross-sectional View taken along the line 5 5 of Fig. 2; and

Fig. 6 is an exploded View illustrating mainly the inlet end of the venturi tube and associated slidable air shutter.

The venturi tube of the present invention is indicated as a whole by the reference character 10` in Fig. l and, as shown, it is intended for use with the top burner of a gas stove. For such use the outlet end 12 of the tube may be bent upwardly as indicated by the reference char- 2,815,070 `Patented Dec. 3, 1957 ICC t acter 14 and a burner supporting xture or ange 16 is mounted at the upturned end. The particular conguration and construction of the bend `and burner receiving xture may vary depending upon the requirements of a particular stove construction.

The venturi tube is made from a piece of uniform diameter metallic tubing which, as indicated above, can be bent at its outlet end for association with a burner. lt includes, inaddition to the outlet end 12, an intermediate venturi section 20 and an inlet end 22. The venturi section 20 includes a throat 24, a gradually diverging outlet portion 26 connected to the outlet end 12, and a steeply converging inlet portion 28 which is connected to the inlet end 22.

In accordance with the present invention, the venturi section is provided with a plurality, such as four, fins 30 which may be formed as by a stamping operation and which results in the doubling of the metal to form the tins, the doubled n defining portions being indicated by the reference characters 30-1 and 30-2 which are connected by a bight portion 30-3, see particularly Fig. 4. The fins are so formed that their outer portions 30-3 are parallel and spaced aparta distance corresponding to the outside diameter of the tube, as is apparent from the drawings. An air controlling shutter, such as the sleevelike shutter 32 is movably mounted upon the inlet end 22 of the tube and the ns 30, whereby there is provided a good and substantial support for the shutter. The shutter is slidably adjustable to control the amount of primary air injection and thus to control the combustible mixture of gas and air supplied to the burner. This control is accomplished by varying the effective size of the several primary air inlet ports 34 formed in the inlet end 22 of the venturi tube.

The air shutter 32 is generally cylindrical in configuration although it is provided with a relatively wide slit 36, see Figs. 2 and 6, so as to encircle and resiliently grip the inlet end 22 and fins 30 of the tube. The shutter is substantially imperforate except that it is provided with an aforementioned slot and with a slot 38 through which extends a screw 40 which can be threaded into the tube to hold the shutter in adjusted position. A slidable shutter is desirable and even necessary in cases Where two venturi tubes are mounted close to each other and even joined at their inlet ends for the supply of gas to a double burner.

The inlet end of the venturi tube is closed by an end plate 42 having a central opening 44 defined by an inwardly extending integral annular ange 46 and into which extends the hood 48 of the fragmentarily illustrated gas valve 50, see Fig. l. The end plate 42 is secured to the tube by peening over the generally semi-- circular end portions 52 so that they encircle the major peripheral portion of the closure plate. The semi-circular parts 52 are separated by the slots 54 which receive the tongue-like projections 56 on the closure plate, thereby effectively to orient the closure plate relative to the tube.

From the foregoing detailed description of the present invention, it is apparent that the tube may be constructed simply and economically and that there is provided a simple and efficient mounting for the air shutter. The shutter is easily mounted upon the venturi tube and adjustable by reason of its being slidably mounted upon the tins and inlet end of the tube, both of which have the same outside dimension. The slidable shutter of the present invention provides a relatively large air inlet area since the shutter can be slid axially from the inlet end onto the fins, whereby the shutter is effectively or mainly supported by the fins in the adjusted position. This construction permits the total effective area of the air inlet openings to exceed fty percent of the total area of the inlet end of the tube. In those constructions where the shutter cannot be slid onto the tins then, in order to obtain the same effective adjustment, the inlet end would have to be extended to provide the necessary support for the shutter in the positions of adjustment providing for maximum air flow. Consequently, some of the tube would have to be used for supporting the shutter vand could not be used as part of the venturi section. In the construction of the present invention the tins are used as supporting means and the tubular inlet end is only of a length required for the air inlet openings so that the venturi section can be lengthened without requiring a corresponding increase in the length of the tube. The construction of the present invention also permits a relatively high iiow of air through the openings with an inlet tube of relatively small diameter. The use of a small diameter tube is important because it reduces play between the inlet connections and the tube, and thus results in holding the tube in fixed position while at the same time preventing excess air leakage between the inlet connections and the tube. Another advantage of the construction whereby the shutter is mounted on both the inlet end and venturi section lins is that it provides for the maximum possible venturi section length with a particular tube. teristics.

While the present invention has been described in connection with the details of an illustrative embodiment, it should be understood that such details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

Having thus described my invention, what I claim as new and desire to be secured by United States Letters Patent is:

1 A venturi tube comprising a tubular member having a rst inlet portion of uniform predetermined outside diameter and a venturi section; said venturi section including a restricted throat intermediate its ends, a converging inlet portion interconnecting the throat and said irst inlet portion, a diverging outlet portion connected to the throat, and a plurality of spaced tins integral with the venturi section, said first inlet portion having air inlet This, in turn, provides better air injection characopening d'eining means formed closely adjacent the tins, and an air shutter at least partially encircling said lirst inlet portion for selectively covering and uncovering thc air inlet opening, said lins and said air shutter being constructed and arranged to permit sliding movement of said shutter axially of said tube a distance equal to the axial extent of the opening and onto at least a portion of said ns in order to uncover the air inlet opening and also to permit reverse sliding movement of the shutter axially of said tube and onto said lirst inlet portion in order to cover said air inlet opening, said tins having a radial extent substantially equal to the radial extent of the first inlet portion for at least a length equal to the sliding distance of the shutter thereon.

2. The apparatus defined by claim 1 wherein said air inlet opening defining means comprises a plurality of air inlet openings which have a total area in excess of 'titty percent of the cylindrical area of the first inlet portion and which are adapted to he covered or uncovered by the air shutter.

3. The apparatus defined by claim 1 wherein the fins extend substantially the length of the throat and the con- References Cited in the file of this patent UNITED STATES PATENTS 1,364,094 Fisher Jan. 4, 1921 2,255,636 Wittmann Sept. 4, 1941 2,355,216 Guelson Aug. 8, 1944 2,694,445 Sassmanhausen Nov. 16, 1954 FOREIGN PATENTS 210,301 Great Britain Jan. 31, 192,4 

